Slalom courese for water skiers



June 2, 1964 B. A. BRETHERTON SLALOM COURSE FOR WATER SKIERS Filed Jan.21, 1965 United States Patent Ofiice 3 ,135,952 Patented June 2, 19643,135,952 SLALOM COURSE FOR WATER SKIERS Bruce Albert Bretherton, 177Power St, Hawthorn, Victoria, Australia Filed Jan. 21, 1963, Ser. No.252,689 Claims priority, application Australia Jan. 26, 1962 9 Claims.(U. 340-482) This invention relates to a slalom course used in the sportof water skiing comprising a zig zag course of uniform pitch andamplitude, marked out on the water by a buoy at each turning point. Theboat towing the skier travels in a straight line midway between thebuoys and the skier attempts to follow the zig zag course passing aroundthe outside of each buoy.

At present all slalom courses are marked by two rows of aligning buoysfloating on the surface of the water and anchored in position, andbetween which rows the towing boat is centrally driven. Considerabletime is required to lay out the slalom course in this manner, whichcourse cannot be left set up in public waters because of the hazard itrepresents to other boats when not in use and particularly at night. Itis thus difficult for skiers to learn and practice slalom skiing excepton the few permanent courses provided on private waterways.

It is therefore the principal object of the present invention to providean apparatus for indicating the turning points of a slalom course to awater skier, which apparatus can be operated from the towing boat, doesnot interfere with other boats in the area, and is effective andaccurate in operation.

With the above stated principal object in view there is providedaccording to the present invention for indicating the turning points ofa slalom course to a water skier being towed by a boat, an apparatuscomprising signal means to indicate to the skier that he is alternatelylocated a distance on either side of the line of travel of the boatcorresponding to the lateral spacing of the turning points from saidline of travel, and intermittent signal means to indicate to the skierregular time intervals corresponding to the time allowed to travel thelongitudinal distance between the turning points commensurate with apredetermined boat speed, whereby the skier can by co-ordinating the twosignal indications, determine the turning points whilst traversing theslalom course.

More specifically there is provided audible or visible signal meansoperable in response to movement of the ski rope to issue a signal whenthe skier is located a lateral distance from the line of travel of theboat corresponding to the lateral spacing of the turning points fromsaid line of travel, and audible or visible signal means arranged toissue a signal to the skier at predetermined regular time intervalscorresponding to the time required to travel the longitudinal distancebetween the turning points, whereby co-ordination by the skier of thetwo signals will indicate the turning points of the slalom course whilsttravelling therethrough.

Conveniently each signal means comprises a light mounted in the boat todirect a beam of light rearwardly towards the skier, each light being ofa different color. One light flashes at regular intervals, the intervalbeing set to correspond to the time available to travel the longitudinaldistance between the turning points at any seiected boat speed; Theother signal light is controlled by a switch actuated by the skiers ,towrope when the rope is inclined at a predetermined angle to, and oneither side of, the line of travel of the boat along the center line ofthe course. The angle at which the switch is actuated is determined bythe lateral spacing of the turning points and the length of the rope.Under championship skiing rules in regard to the length of the ski-ropeand the spacing of the turning points from the line of travel of theboat the angle is 30.

The provision of these two lights enables the skier to know when he isoffset or displaced the correct lateral distance from the line of travelof the boat and if he is arriving at this point within the time allowedby the spacing of the buoys of a standard slalom course and the speed ofthe boat.

The invention will be more readily understood from the followingdescription of one practical arrangement of the apparatus with referenceto the accompanying drawings.

In the drawings: v

'FIG. 1 is a diagrammatic layout of a slalom water ski course inaccordance with the prevailing international rules for championshipwater skiing.

FIG. 2 is a plan view of the apparatus.

FIG. 3 is an elevation of the apparatus.

FIG. 4 is a sectional view along line 4-4 in FIG. 3.

FIG. 5 is a detailed view of the ski rope clip taken in the direction 55in FIG. 3, and

FIG. 6 is a schematic diagram of the electrical circuit of theapparatus.

Referring now to FIG. 1, in a championship water ski slalom course theturning points normally indicated by the buoys it) are located twelveand one half yards on either side of the center line 11 of the course,and the longitudinal distance between successive turning points, whichare located on opposite sides of the center line of the course, is fortyfive yards. The ski rope 12 by which the skier is towed through thecourse by the boat13 is twenty five yards long, and thus when the skieris rounding one of the buoys the angle x that the ski rope makes withthe line of travel of the boat is 30. In completion the skier is towedthrough the course a number of times until he fails to negotiate one ofthe buoys marking the turning points. The speed of the boat is increasedin steps of 2 mph. on each successive pass through the course, the firstpass being made at 24 mph In order to simplify the following descriptionof the apparatus we shall assume that theapparatus is adjusted toindicate the turning points of the above described champion-ship slalomcourse when the boat is travelling 'at 30 mph.

The appaartus comprises a housing 15 mounted upon the upper end of aconventionalski-pole 16 secured to the boat. The rear section of thehousing is made up of two lamp lines 17 and 18 colored red and orangerespec-.

tively. Electric globes RL and OL are located behind the respective lensand are energized as hereinafter described so that the longitudinalspacing of the turning points is indicated by a red light and thelateral spacing by an orange light. v

Mounted in the housing 15 is the micro switch 20 which controls the flowof current from the battery B to the globe 0L behind the orange lens(FIG. 5). The switch 29 is pivotally connected to the base of thehousing 15' by the screw 21. The adjustingscrew 22 is in threadedengagement with the nut 23 secured in the side wall 24- of the housingand an inner tapered end 25 of the screw engages the projection 26 onthe micro switch 20 to permit adjustment of the position of actuatingroller 27 of the switch relative to the cam 30.

The cam 30 is attached to the shaft 31 which is journalled in andprojects downwardly through thebas'e of the housing. The actuating arm32 is attached to the lower end or" the shaft 31 and carries at the rearmost end a rope clip 33. The clip comprises two resilient legs 34 joinedat the upperend and abutting each other at the lower end 36' to form anelongated'loop through which the ski rope 12 passes. If the ski ropebecomes entangled in the propeller of the boat or some othersubmergedobject the downward pull on the rope will automatically free the ropefrom the clip and prevent damage to the apparatus.

The ski rope is attached to the hook 40 on the ski-pole 16 which isforward of the rope clip 33 and thus, as the skier moves laterallyoutwards from the line of travel of the boat, the actuating arm 32 willeffect a partial rotation of the shaft 31 and cam 30. The contour of thecam and the relative disposition of the switch is arranged so that uponthe ski rope attaining an inclination of 30 to the line of travel of theboat, on either side thereof, the switch 20 will close and energize theglobe 0L so as to show an orange light to the skier. As previouslyexplained this angular disposition of the ski-rope corresponds to theskier being laterally displaced from the line of travel of the boat adistance correspondingto the lateral spacing of the turning points ofthe slalom course.

In order to indicate to the skier the longitudinal spacing of theturning points of the slalom course the globe RL behind the red lens 17is connected to the battery B by any one of the known automatic flashingcircuits PC which will effect a regular flashing of the globe RL. Theflashing circuit includes a control which permits variation of the timewhich elapses between each flash of the globe RL so that this time canbe set to suit diiferent boat speeds, e.g. when the boat is travellingat mph it will take approximately 3 seconds for the boat to travel theyards between successive turning points in the course and thus the globeRL would flash at 3 seconds intervals.

With the energization of the two globes 0L and RL controlled in thismanner the skier can ascertain from the orange light when he has moved asufiicient distance laterally from the line of travel of the boat topass around the turning point of the slalom course, and the regularlyflashing red light indicates if this position is reached with the timeavailable in accordance with the longitudinal spacing of the turningpoint and the particular speed of the boat. The skier is on courseif theorange light flashes before or at the same time as the red lightflashes, but if the red light flashes first it indicates that the skieris travelling too slow to reach the turning point within the availabletime.

Ii desired the circuit of the orange light can be interconnected to theautomatic flashing circuit of the red light so that if the orange lightis energized before the red light has flashed then the approaching flashof the red light will be cancelled and the flashing circuit willimmediately commence to measure the period for the next flash of the redlight. In this manner whilst the skier continues to travel at suflicientspeed to achieve Lhe required lateral displacement within the timeallowed he will only see flashes from the orange light. The red light'will only flash when the skier fails to reach the lateral displacementwithin the allowed time.

In another modification of the apparatus the red light indicating thelongitudinal spacing of the turning points may be arranged to flash ateach turning point in the course and also at a point midway between thesuccessive turning points. This intermediate flash of the red lightwould correspond to the time when the skier should be crossing the lineof travel of the boat between each turning point, and thus indicates tothe skier whether he is on course or whether he must increase his speedin order to reach the next turning point on time.

In the foregoing description reference has been made to the dimensionsof a championship slalom course, however the apparatus according to thepresent invention can be used to produce a course of any desireddimensions and is particularly advantageous for learner skiers as thecourse can be set initially to make completion of it simple and thenadjusted gradually up to championship conditions as the skiers abilityimproves.

It will also be realised that the automatic flashing cir cuitcontrolling the red light which indicates the longitudinal spacing ofthe turning points can be set to indi- 4 cate this spacing at any boatspeed independent of the actual s eed of the boat, i.e. for a speedfaster, slower or equal to the actual boat speed. In this manner alearner skier can practice at a slalom speed of 15 mph, behind a boattra'elling at 25 mph. and an expert skier can practice at a slalom speedof 40 mph with a boat travelling at a speed of 32 mph. This arrangementallovs the learner skier more time to reach the turning points and yetthe boat can travel at a sufiiciently fast speed to provide adequatelift to the ski by the water, and permits the expert skier to practiceat a slalom speed higher than the maximum speed attainable by the boat.

Although the apparatus described herein has incorporated differentcolored lights as the signal means it is to be understood that horns orother electrically operated audio devices of different tones may be usedto replace, or in combination with the lights.

I claim:

1. For indicating the turning points of a slalom course to a water skierbeing towed by a boat, an apparatus comprising signal means to indicateto the skier that he is alternately located a distance on either side ofthe line of travel of the boat corresponding to the lateral spacing ofthe turning points from said line of travel, and intermittent signalmeans to indicate to the skier regular time intervals corresponding tothe time allowed to travel the longitudinal distance between the turningpoints commensurate with a predetermined boat speed, whereby the skiercan by co-ordinating the two signal indications, determine the turningpoints whilst traversing the slalom course.

2. For indicating the turning points of a slalom course to a water skierbeing towed by a boat, an apparatus comprising audible or visible signalmeans operable in response to movement of the ski rope to issue a signalto the skier that he is alternately located a lateral distance from andon either side of the line of travel of the boat corresponding to thelateral spacing of the turning points from said line of travel, andaudible or visible signal means arranged to issue an intermittent signalto the skier at regular time intervals corresponding to the time allowedto travel the longitudinal distance between the turning pointscommensurate with a predetermined boat speed, whereby co-ordination bythe skier of the two signals whilst traversing the slalom course willindicate the turning points thereof.

3. An apparatus for fitment to a boat to indicate the turning points ofa slalom course to a water skier being towed by a ski rope attached tothe boat comprising lateral signal means operable by the ski rope uponthe latter attaining a predetermined inclination to and on either sideof the line of travel of the boat to indicate to the skier that he islaterally displaced from the line of travel of the boat a distance equalto the lateral spacing of the turning points from said line of travel,and longitudinal signal means constructed and arranged to emit anintermittent signal at regular time intervals corresponding to the timeallowed to travel the longitudinal distance between the turning pointscommensurate with a predetermined boat speed, whereby co-ordination bythe skier of the two signals whilst traversing the slalom course willindicate the turning points of the course.

4. An apparatus as claimed in claim 3, wherein the lateral andlongitudinal signal means comprise separate light sources arranged todirect beams of light of different colors towards the skier.

5. An apparatus as claimed in claim 3, wherein the lateral signal meanscomprises a colored light source, an electrical power supply to energizesaid light source, a switch to selectively connect said power supply tosaid light source and a cam actuated in response to the relativemovement between the ski-rope and the boat as the skier moves in alateral direction relative to the line of travel of the boat, said cambeing arranged to operate the switch and energize the light source whenthe ski rope attains the predetermined inclination to and on either sideof the line of travel of the boat.

6. An apparatus as claimed in claim 5, wherein the longitudinal signalmeans comprises a different colored light source, a flashing controlcircuit connecting said different colored light source to saidelectrical power supply and constructed and arranged to energize saiddifferent colored light source at regular intervals so as to emit anintermittent flash, and means within said circuit to adjust the periodof said intervals to correspond to the time allowed to travel thelongitudinal distance between the turning points in accordance with theboat speed.

7. An apparatus for fitment to a boat to indicate the turning points ofa slalom course to a Water skier being towed by a ski-rope attached tosaid boat comprising a housing adapted for attachment to the boat, twolight compartments forming at least part of the rear of said housing, anelectric light globe mounted in each light compartment, a translucentportion in each light compartment constructed and arranged so that beamsof different colored light are directed towards the skier when therespective globes are energized, an electrical power supply to energizesaid globes, a switch mounted in the housing to selectively connect oneof the globes to said power supply, a cam mounted in said housing forrelative angular movement, an actuating arm connected to said cam anddisposed externally of that housing, said actuating arm being adaptedfor coupling to the ski-rope so as to eifect angular movement of the camas the ski-rope adopts an inclination to the line of travel of the boat,the cam 6 being shaped and arranged relative to the switch to actuatethe latter and flash said onset the globes upon the skirope attaining apredetermined inclination to and on either side of the line of travel ofthe boat corresponding to the skier being located a lateral distancefrom said line of travel equivalent to the lateral spacing of theturning points of the course, a flashing control circuit connecting theother globe to the electric power supply and arranged to energize saidother globe at regular intervals, and,

control means in said circuit to adjust the period of said intervals tocorrespond to the time allowed to travel the longitudinal distancebetween the turning points in accordance with the boat speed, wherebythe skier can ascertain the turning points of the slalom course byco-ordinating the flashes from the respective globes.

8. An apparatus as claimed in claim 7, wherein the flashing controlcircuit is interconnected with the switch and arranged so that if theswitch is actuated before the said other globe is flashed the flashingcontrol circuit is reset to commence timing of the interval for the nextflash of said other globe.

9. An apparatus as claimed in claim 7, wherein the flashing controlcircuit is constructed and arranged so that the interval between flashesof the other globe is equal to one half of the time allowed to travelthe longitudinal distance between the turning points whereby thealternate flashes indicate when the skier should be crossing the line oftravel of the boat.

No references cited.

3. AN APPARATUS FOR FITMENT TO A BOAT TO INDICATE THE TURNING POINTS OFA SLALOM COURSE TO A WATER SKIER BEING TOWED BY A SKI ROPE ATTACHED TOTHE BOAT COMPRISING LATERAL SIGNAL MEANS OPERABLE BY THE SKI ROPE UPONTHE LATTER ATTAINING A PREDETERMINED INCLINATION TO AND ON EITHER SIDEOF THE LINE OF TRAVEL OF THE BOAT TO INDICATE TO THE SKIER THAT HE ISLATERALLY DISPLACED FROM THE LINE OF TRAVEL OF THE BOAT A DISTANCE EQUALTO THE LATERAL SPACING OF THE TURNING POINTS FROM SAID LINE OF TRAVEL,AND LONGITUDINAL SIGNAL MEANS CONSTRUCTED AND ARRANGED TO EMIT ANINTERMITTENT SIGNAL AT REGULAR TIME INTERVALS CORRESPONDING TO THE TIMEALLOWED TO TRAVEL THE LONGITUDINAL DISTANCE BETWEEN THE TURNING POINTSCOMMENSURATE WITH A PREDETERMINED BOAT SPEED, WHEREBY CO-ORDINATION BYTHE SKIER OF THE TWO SIGNALS WHILST TRAVERSING THE SLALOM COURSE WILLINDICATE THE TURNING POINTS OF THE COURSE.